"Really, the main personality of Bane's voice had to come from Tom and his performance," Nolan said in the 'Gotham's Reckoning' mini-documentary on The Dark Knight Rises Blu-ray.

"And what he did with it was extremely surprising at first. It's an extremely peculiar take on what the voice would be - but once you've heard it for five minutes or so it becomes essential to the character."

Hardy said that the voice was supposed to indicate someone prematurely aged from being in constant agony.

"As soon as you put on a mask as an actor, you have the freedom to adopt a character," he said. "Like [on] Halloween, you put on a mask and you could be absolutely anybody."

He added that his vocal performance was like Richard Burton or "a camp English villain in many ways, but just off-centre".

"Tom is a very bold actor; he had some wonderful ideas about how Bane should sound," added Bale. "I thought it was a great collection of inspirations that Tom chose."